Quinazolinone derivatives useful as vanilloid antagonists

ABSTRACT

The present invention relates to the use of a quinazolinone compound of the formula (I) wherein R 1 , R 2 , R 3 , R 4 , R 5  and m are as defined in the specification and in the claims, in free form or in salt form, and, where possible, in acid addition salt form, as a vanilloid.

The present invention relates to the use of quinazolinone derivatives as vanilloid antagonists, to certain novel quinazolinone derivatives, to processes for preparing them, to their use as pharmaceuticals and to pharmaceutical compositions containing them.

In a first aspect, the present invention relates to the use of a quinazolinone compound of the formula

wherein

-   -   R₁ is C₁-C₆alkyl, (C₁-C₆alkyl)C₁-C₆alkyl,         di-(C₁-C₆alkyl)C₁-C₆alkyl, C₃-C₆cycloalkyl, (C₁-C₆alkyl)amino or         di-(C₁-C₆alkyl)amino;     -   each R₂, independently, is halogen, C₁-C₆alkyl,         halogen-substituted C₁-C₆alkyl, hydroxyC₁-C₆alkyl, cyano or a         group —C(═O)—R_(2a), where R_(2a) is C₁-C₆alkyl;     -   R₃ is hydrogen, halogen, C₁-C₆alkyl, C₂-C₆alkenyl, C₂-C₆alkynyl,         hydroxy, hydroxy-substituted C₁-C₆alkyl, C₁-C₆alkoxy,         C₃-C₆cycloalkyl, cyano, —C(═O)H, phenyl,         (C₃-C₆cycloalkyl)C₁-C₆alkoxy,         (C₁-C₆alkoxycarbonylamino)C₁-C₆alkoxy or         (C₁-C₆alkylcarbonylamino)C₁-C₆alkoxy;     -   R₄ is hydroxy, esterified hydroxy, etherified hydroxy, amino,         (C₁-C₆alkyl)amino, a group

-   -    or a group

-   -    where R_(4a) is C₁-C₆alkyl or halogen-substituted C₁-C₆alkyl,         or a group

-   -    where R_(4a) is benzyl or phenylethyl;     -   R₅ is hydrogen or hydroxy; and     -   m is 1 or 2,         in free form or in salt form, and, where possible, in acid         addition salt form, as a vanilloid antagonist.

In a special embodiment of the first aspect, the present invention relates to the use of a quinazolinone compound of the formula I, wherein

-   -   R₁ is C₁-C₆alkyl, (C₁-C₆alkyl)C₁-C₆alkyl,         di-(C₁-C₆alkyl)C₁-C₆alkyl or C₃-C₆cycloalkyl;     -   each R₂, independently, is halo, C₁-C₆alkyl, tri-halo         substituted C₁-C₆alkyl, hydroxyC₁-C₆alkyl or a group

-   -    where R_(2a) is C₁-C₆alkyl;     -   R₃ is hydrogen, halo, C₁-C₆alkyl, hydroxy, C₁-C₆alkoxy or         (C₃-C₆cycloalkyl)C₁-C₆alkoxy;     -   R₄ is hydroxy, esterified hydroxy, etherified hydroxy, amino,         (C₁-C₆alkyl)amino, a group

-   -    or a group

-   -    where R_(4a) is C₁-C₆alkyl, or a group

-   -    where R_(4b) is benzyl or phenylethyl;     -   R₅ is hydrogen or hydroxy; and     -   m is 1 or 2,         in free or salt form and, where possible, in acid addition salt         form, as a vanilloid antagonist.

In a second aspect, the present invention relates to novel quinazolinone compounds of the formula

wherein

-   -   R₁ is C₁-C₆alkyl, (C₁-C₆alkyl)C₁-C₆alkyl,         di-(C₁-C₆alkyl)C₁-C₆alkyl, C₃-C₆cycloalkyl, (C₁-C₆alkyl)amino or         di-(C₁-C₆alkyl)amino;     -   each R₂, independently, is halogen, C₁-C₆alkyl,         halogen-substituted C₁-C₆alkyl, hydroxyC₁-C₆alkyl, cyano or a         group —C(═O)—R_(2a), where R_(2a) is C₁-C₆alkyl;     -   R₃ is hydrogen, halogen, C₁-C₆alkyl, C₂-C₆alkenyl, C₂-C₆alkynyl,         hydroxy, hydroxy-substituted C₁-C₆alkyl, C₁-C₆alkoxy,         C₃-C₆cycloalkyl, cyano, —C(═O)H, phenyl,         (C₃-C₆cycloalkyl)C₁-C₆alkoxy,         (C₁-C₆alkoxycarbonylamino)C₁-C₆alkoxy or         (C₁-C₆alkylcarbonylamino)C₁-C₆alkoxy;     -   R₄ is hydroxy, esterified hydroxy, etherified hydroxy, amino,         (C₁-C₆alkyl)amino, a group

-   -    or a group

-   -    where R_(4a) is C₁-C₆alkyl or halogen-substituted C₁-C₆alkyl,         or a group

-   -    where R_(4b) is benzyl or phenylethyl; and     -   m is 1 or 2,         in free form or in salt form, and, where possible, in acid         addition salt form.

In a special embodiment of the second aspect, the present invention relates to novel quinazolinone compounds of the formula Ia, wherein

-   -   R₁ is C₁-C₆alkyl, (C₁-C₆alkyl)C₁-C₆alkyl,         di-(C₁-C₆alkyl)C₁-C₆alkyl or C₃-C₆cycloalkyl;     -   each R₂, independently, is halo, C₁-C₆alkyl, tri-halo         substituted C₁-C₆alkyl, hydroxyC₁-C₆alkyl or a group

-   -    where R_(2a) is C₁-C₆alkyl;     -   R₃ is hydrogen, halo, C₁-C₆alkyl, hydroxy, C₁-C₆alkoxy or         (C₃-C₆cycloalkyl)C₁-C₆alkoxy;     -   R₄ is hydroxy, esterified hydroxy, etherified hydroxy, amino,         (C₁-C₆alkyl)amino, a group

-   -    or a group

-   -    where R_(4a) is C₁-C₆alkyl, or a group

-   -    where R_(4b) is benzyl or phenylethyl; and     -   m is 1 or 2,         in free or salt form and, where possible, in acid addition salt         form.

Terms used in this specification have the following meanings:

“C₁-C₆alkyl” denotes straight-chain or branched C₁ to C₆-alkyl, e.g., methyl ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl.

-   -   “C₁-C₆alkoxy” denotes straight-chain or branched C₁ to         C₆-alkyl-oxy, e.g., methoxy, ethoxy, n-propoxy or isopropoxy.

“Halo” denotes halogen which may be I, Br, Cl or F.

“Esterified hydroxy” denotes acyloxy, preferably C₁-C₆alkanoyloxy, more preferably C₁-C₄alkanoyloxy.

“Etherified hydroxy” denotes C₁-C₆alkoxy, preferably C₁-C₄alkoxy.

The quinazolinone compounds of the invention exist in free or salt form and, where possible, in acid addition salt form. The invention is to be understood as including the compounds of formulae (I) and (Ia) in free or salt form and, where possible, in acid addition salt form. In the latter connection, suitable pharmaceutically acceptable acid addition salts for pharmaceutical use in accordance with the invention include, in particular, the hydrochloride salt.

In formulae (I) and (Ia), the following significances are preferred independently, collectively or in any combination or sub-combination:

-   -   (a) R₁ is C₁-C₄alkyl, (C₁-C₄alkyl)C₁-C₄alkyl,         di-(C₁-C₄alkyl)C₁-C₄alkyl or cyclopropyl;     -   (b) each R₂, independently, is chloro, fluoro, C₁-C₄alkyl,         trifluoro-substituted C₁-C₄alkyl, more preferably         trifluoromethyl, C₁-C₄alkylcarbonyl, more preferably         methylcarbonyl, or hydroxyC₁-C₄alkyl, more preferably         hydroxymethyl;     -   (c) R₃ is hydrogen, chloro, bromo, C₁-C₄alkyl, hydroxy,         C₁-C₄alkoxy or (C₃-C₈cycloalkyl)C₁-C₄alkoxy; and     -   (d) R₄ is hydroxy, amino, (C₁-C₄alkyl)amino or a group

-   -    where R_(4a) is C₁-C₄alkyl.

In a third aspect, the present invention relates to processes for preparing the compounds of formula (Ia) as depicted in the following reaction schemes:

A. For preparing compounds of formula (Ia), where R₁ and R₂ are as defined above, R₃ is as defined for a compound of formula I, R₄ is amino and m is 1.

General Description:

The first step of Scheme A involves the condensation/cyclisation of the amide compound of formula 1 with a substituted aniline compound in the presence of phosphorus trichloride to obtain the 7-nitro substituted quinazolin-4-one compound of formula 2.

Second Step:

General Description:

The second step of Scheme A involves the reduction of the 7-nitro substituted quinazolin-4-one compound of formula 2 with glacial acetic acid and iron powder to obtain the 7-amino substituted quinazolin-4-one compound of formula 3.

The corresponding alkylamines, amides and carbamates may be prepared by methods described in the literature utilising a compound of formula 3. More particularly, the alkylamines may be prepared by subjecting a compound of formula 3 to reductive alkylation utilising an appropriate aldehyde or ketone. Alternatively, a compound of formula 3 may be reacted with a C₁-C₆alkyl halide. The amides may be prepared by acylating a compound of formula 3 with an appropriate acyl chloride. The carbamates may be prepared by reacting a compound of formula 3 with an appropriate alkylchloroformate.

B. For preparing compounds of formula (Ia), where R₁ and R₂ are as defined above, R₃ is as defined for a compound of formula I, R₄ is hydroxy and m is 1.

General Description:

Scheme B involves the Sandmeyer reaction of the 7-amino substituted quinazolin-4-one compound of formula 3 which was prepared as set forth in Scheme A, with concentrated sulphuric acid and sodium nitrite to obtain the 7-hydroxy substituted quinazolin-4-one compound of formula 4.

The starting compounds in Scheme A are known compounds which are commercially available.

Working up the reaction mixtures according to the above processes and purification of the compounds thus obtained may be carried out in accordance with known procedures.

Acid addition salts may be produced from the free bases in known manner, and vice-versa.

Compounds of formulae (I) and (Ia) in optically pure form can be obtained from the corresponding racemates according to well-known procedures, e.g., HPLC with chiral matrix. Alternatively, optically pure starting materials can be used.

Stereoisomeric mixtures, e.g., mixtures of diastereomers, can be separated into their corresponding isomers in a manner known per se by means of suitable separation methods. Diastereomeric mixtures, e.g., may be separated into their individual diastereomers by means of fractionated crystallisation, chromatography, solvent distribution and similar procedures. This separation may take place either at the level of a starting compound or in a compound of formula (I) or (Ia) itself. Enantiomers may be separated through the formation of diastereomeric salts, e.g., by salt formation with an enantiomer-pure chiral acid, or by means of chromatography, e.g., by HPLC, using chromatographic substrates with chiral ligands.

In any additional process steps, carried out as desired, functional groups of the starting compounds which should not take part in the reaction may be present in unprotected form or may be protected, e.g., by one or more of the protecting groups mentioned below. The protecting groups are then wholly- or partly-removed according to one of the methods described there.

The protecting groups may already be present in precursors and should protect the functional groups concerned against unwanted secondary reactions. It is a characteristic of protecting groups that they lend themselves readily, i.e., without undesired secondary reactions, to removal, typically by solvolysis, reduction, photolysis or also by enzyme activity, e.g., under conditions analogous to physiological conditions, and that they are not present in the end-products. The skilled artisan knows, or can easily establish, which protecting groups are suitable with the reactions mentioned hereinabove and hereinafter.

The protection of such functional groups by protecting groups, the protecting groups themselves, and their removal reactions are described, e.g., in standard reference works, such as J. F. W. McOmie, Protective Groups in Organic Chemistry, Plenum Press, London and NY (1973); T. W. Greene, Protective Groups in Organic Synthesis, Wiley, NY (1981); The Peptides; Volume 3, E. Gross and J. Meienhofer, Eds., Academic Press, London and NY (1981); Methoden der organischen Chemie (Methods of organic chemistry), Houben Weyl, 4^(th) Edition, Volume 15/1, Georg Thieme Verlag, Stuttgart (1974); H. D. Jakubke and H. Jescheit, Aminosauren, Peptide, Proteine (Amino acids, peptides, proteins), Verlag Chemie, Weinheim, Deerfield Beach, and Basel (1982); and Jochen Lehmann, Chemie der Kohlenhydrate: Monosaccharide and Derivate (Chemistry of carbohydrates: monosaccharides and derivatives), Georg Thieme Verlag., Stuttgart (1974).

All process steps described herein can be carried out under known reaction conditions, preferably under those specifically mentioned, in the absence of or usually in the presence of solvents or diluents, preferably such as are inert to the reagents used and able to dissolve these, in the absence or presence of catalysts, condensing agents or neutralizing agents, e.g., ion exchangers, typically cation exchangers, e.g., in the H⁺ form, depending on the type of reaction and/or reactants at reduced, normal or elevated temperature, e.g., in the range from −100° C. to about 190° C., preferably from about −80° C. to about 150° C., e.g., at −80° C. to 60° C., at room temperature, at −20° C. to 40° C. or at the boiling point of the solvent used, under atmospheric pressure or in a closed vessel, where appropriate under pressure, and/or in an inert atmosphere, e.g., under argon or nitrogen.

Preferred compounds of formula (I) are those wherein

-   R₁ is C₁-C₄alkyl, (C₁-C₄alkyl)C₁-C₄alkyl or C₃-C₆cycloalkyl; -   R₂ is chloro, fluoro, C₁-C₄alkyl, trifluoro-substituted C₁-C₄alkyl,     C₁-C₄alkylcarbonyl or hydroxyC₁-C₄alkyl; -   R₃ is hydrogen, chloro, bromo, hydroxy, C₁-C₄alkyl, hydroxy,     C₁-C₄alkoxy or (C₃-C₆cycloalkyl)C₁-C₄alkoxy, -   R₄ is hydroxy, amino or (C₁-C₄alkyl)amino; -   R₅ is hydrogen or hydroxy; and -   m is 1 or 2.

More preferred compounds of formula (I) are those wherein

-   R₁ is C₁-C₄alkyl, (C₁-C₄alkyl)C₁-C₄alkyl or C₃-C₆cycloalkyl; -   R₂ is chloro, fluoro, C₁-C₄alkyl, trifluoromethyl, methylcarbonyl or     hydroxymethyl; -   R₃ is hydrogen, chloro, bromo, C₁-C₄alkyl, hydroxy or C₁-C₄alkoxy; -   R₄ is hydroxy, amino or (C₁-C₄alkyl)amino; -   R₅ is hydrogen or hydroxy; and -   m is 1.

Preferred compounds of formula (Ia) are those wherein

-   R₁ is C₁-C₄alkyl, (C₁-C₄alkyl)C₁-C₄alkyl or C₃-C₆cycloalkyl; -   R₂ is chloro, fluoro, C₁-C₄alkyl, trifluoro-substituted C₁-C₄alkyl,     C₁-C₄alkylcarbonyl or hydroxyC₁-C₄alkyl; -   R₃ is hydrogen, chloro, bromo, C₁-C₄alkyl, hydroxy, C₁-C₄alkoxy or     (C₃-C₆cycloalkyl)C₁-C₄alkoxy; -   R₄ is hydroxy, amino or (C₁-C₄alkyl)amino; and -   m is 1 or 2.

More preferred compounds of formula (Ia) are those wherein

-   R₁ is C₁-C₄alkyl, (C₁-C₄alkyl)C₁-C₄alkyl or C₃-C₆cycloalkyl; -   R₂ is chloro, fluoro, C₁-C₄alkyl, trifluoromethyl, methylcarbonyl or     hydroxymethyl; -   R₃ is hydrogen, chloro, bromo, C₁-C₄alkyl, hydroxy, C₁-C₄alkoxy or     (C₃-C₆cycloalkyl)C₁-C₄alkoxy; -   R₄ is hydroxy, amino or (C₁-C₄alkyl)amino; and -   m is 1.

The even more preferred compounds of the formula I or Ia are the compounds of the Examples 1 to 29, especially of the Examples 1 to 28.

Another aspect of this invention relates to the fact that the compounds of formulae (I) and (Ia) and their pharmaceutically acceptable salts and, where possible, pharmaceutically acceptable acid addition salts, have beneficial pharmacological activity and, therefore, are useful as pharmaceuticals. In particular, the compounds of formulae (I) and (Ia) exhibit human vanilloid antagonistic activity. More particularly, the compounds of formulae (I) and (Ia) are active at the TRPVI receptor as demonstrated by their ability to inhibit capsaicin and low pH activation of the TRPVI ion channel as follows:

Chinese Hamster Ovary-K1 (CHO-K1) cells, transfected to express either the human, rat or guinea pig TRPV1 receptor, were grown in Minimal Essential Media (MEM) alpha medium without nucleosides supplemented with fetal calf serum (10%), 2 mM L-glutamine, 100 IU/mL penicillin, 100 μg/mL streptomycin and 350-700 μg/mL geneticin. All reagents were supplied by Invitrogen. Cells were grown in T-175 flasks or Costar black, clear-bottomed 96-well view plates and maintained at 37° C. in a 90% humidified incubator with an atmosphere of 5% CO₂ and 95% air. The cells were passaged twice a week at a ratio of 1:10 to 1:20 to maintain steady growth. For experimentation, cells were harvested at approximately 80% confluency and plated onto view plates at 40,000 cells per well in 100 μL media and grown overnight.

Calcium Mobilisation Assay

On the day of the capsaicin assay, media was aspirated and cells were washed with 100 μL 10 mM N-2-(hydroxyethylpiperazine-N′-[2-ethane-sulfonic acid] (HEPES) buffered Hank's Balanced Salt Solution (HBSS), pH 7.4. Cells were then incubated for 40 minutes with 2.3 μM of the ratiometric calcium binding dye fura-2/AM (from Molecular Probes), made up in HEPES buffered HBSS, containing 0.01% pluronic F-127. For the pH assay, HEPES was omitted and the pH of HBSS adjusted to 7.4. After washing twice with 100 μL assay buffer, cells were incubated for 10 minutes with 100 μL of test compounds (made up in HBSS, pH 7.4), in duplicate, at concentrations between 0.001 and 30 μM. The plate was then placed in a Molecular Devices Flexstation. The TRPV1 receptor was stimulated by application of either capsaicin or low pH. For testing the effect of compounds for possible antagonism, capsaicin was used at the EC₈₀ concentration which was 0.05 μM for the rat TRPV1 receptor, and 0.1 μM for the human and guinea pig. For pH experiments, a low pH buffered solution [60 mM 2-[N-morpholino]ethane sulfonic acid (MES) in HBSS] was added to the assay wells to give a final pH of 5.5.

For determinations of antagonist IC₅₀ values (concentrations of antagonist that inhibit responses to either pH 5.5 or capsacin by 50%), at least 10 antagonist concentrations were measured in duplicate. The response in the presence of the antagonist was calculated as a percentage of the control response to capsaicin or low pH and was plotted against the concentration of antagonist. The IC₅₀ was estimated by non-linear regression analysis to sigmoidal-logistic curves by Activity-Base software (v5.0.10) or Microcal Origin (v7.03). These values were averaged (means and standard error of the mean) for at least three independent experiments.

The compounds of formulae (I) and (Ia), e.g., the compounds of Examples 1-28, show TRPVI receptor antagonist activity having IC₅₀ values in the range 0.004-30 μM.

In view of the above, the compounds of formulae (I) and (Ia) are useful as vanilloid receptor blockers, e.g., in the treatment of diseases and conditions in which vanilloid receptor activation plays a role or is implicated. Such conditions include, in particular, pain, e.g., bone and joint pain (osteoarthritis), cancer pain, myofascial pain (muscular injury, fibromyalgia) and perioperative pain (general surgery, gynecologic surgery).

The compounds of formulae (I) and (Ia) are particularly useful In the treatment or prevention of chronic pain, especially inflammatory, e.g., chronic inflammatory pain; inflammatory diseases, e.g., inflammatory airways disease, e.g., chronic obstructive pulmonary disease (COPD), or in asthma; cough; urinary incontinence; migraine; visceral disorders, e.g., inflammatory bowel disease; rhinitis; cystitis, e.g. interstitial cystitis; pancreatitis; uveitis; inflammatory skin disorders; and rheumatoid arthritis.

The compounds of formulae (I) and (Ia) are thus useful as vanilloid receptor antagonists, e.g., for the treatment of pain of various genesis or aetiology and as anti-inflammatory and/or anti-edemic agents for the treatment of inflammatory reactions, diseases or conditions, as well as for the treatment of allergic responses. Having regard to their analgesic/anti-inflammatory profile, they are useful for the treatment of inflammatory pain, for the treatment of hyperalgesia and, in particular, for the treatment of severe chronic pain. They are, e.g., useful for the treatment of pain, inflammation and/or oedema consequential to trauma, e.g., associated with burns, sprains, fractures or the like, subsequent to surgical intervention, e.g., as post-operative analgesics, as well as for the treatment of inflammatory pain of diverse genesis, e.g., for the treatment of osteo and rheumatoid arthritis and rheumatic disease, teno-synovitis and gout. They are further suitable as analgesics for the treatment of pain associated with, e.g., angina, menstruation or cancer. As anti-inflammatory/anti-oedema agents, they are further useful, e.g., for the treatment of inflammatory skin disorders, e.g., psoriasis and eczema.

As vanilloid receptor blockers, the compounds of formula (I) and (Ia) are also useful as smooth muscle relaxants, e.g., for the treatment of spasm of the gastrointestinal tract or uterus, e.g., in the therapy of Crohn's disease, ulcerative colitis or pancreatitis.

The compounds of formula (I) and (Ia) are in particular useful as agents for the therapy of airways hyperreactivity and for the treatment of inflammatory events associated with airways disease, in particular, asthma. In addition, the agents of invention may, e.g., be used for the control, restriction or reversal of airways hyperreactivity in asthma.

Inflammatory or obstructive airways diseases to which the present invention is applicable include asthma of whatever type or genesis including both intrinsic and, especially, extrinsic asthma. Thus, the compounds of formula (I) and (Ia) are useful for the treatment of allergic asthma, as well as, e.g., exercise induced asthma, occupational asthma, asthma induced following bacterial infection, other non-allergic asthmas and “wheezy-infant syndrome”.

Efficacy in the treatment of asthma will be evidenced by reduced frequency or severity of symptomatic attack, e.g., of acute asthmatic or bronchoconstrictor attack and by reduced requirement for other, symptomatic therapy, e.g., anti-inflammatory, e.g., corticosteroid; or bronchodilator, e.g., β2 adrenergic, therapy.

Inflammatory or obstructive airways diseases to which the present invention is applicable further include pneumoconiosis (an inflammatory, commonly occupational, disease of the lungs, frequently accompanied by repeated inhalation of dusts) of whatever type or genesis including, e.g., aluminosis, anthracosis, asbestosis, chalicosis, ptilosis, siderosis, silicosis, tabacosis and, in particular, byssinosis.

Further inflammatory or obstructive airways diseases and conditions for which the compounds of formulae (I) and (Ia) may be used include adult respiratory distress syndrome (ARDS), chronic obstructive pulmonary or airways disease (COPD or COAD), and bronchitis. The compounds of formulae (I) and (Ia) may also be used for the treatment of allergic and vasomotor rhinitis.

In addition to the foregoing, the compounds of formulae (I) and (Ia) are also indicated for use in the therapy of septic shock, e.g., as anti-hypovolaemic and/or anti-hypotensive agents; in the treatment of inflammatory bowel disease; cerebral oedema; headache; migraine; inflammatory skin disease, such as eczema and psoriasis; inflammatory disorders of the gut, e.g., irritable bowel syndrome; Crohn's disease; ulcerative colitis; and cystitis, e.g., interstitial cystitis, nephritis and uveitis.

The agents of the invention are useful in the prevention and treatment of diseases and conditions in which human VR1 activation plays a role or is implicated, and therefore susceptible to treatment by the modulation (preferably antagonism) of VR1 receptors. Such conditions include chronic pain with an inflammatory component such as rheumatoid arthritis; bone and joint pain (osteoarthritis); post-surgical pain; musculo-skeletal pain such as fibromyalgia; myofascial pain syndromes; headache, including migraine, acute or chronic tension headache, cluster headache, temporomandibular pain, and maxillary sinus pain; ear pain; episiotomy pain; burns, and especially primary hyperalgesia associated therewith; deep and visceral pain, such as heart pain, muscle pain, eye pain, orofacial pain, abdominal pain, gynaecological pain, such as dysmenorrhoea, and labour pain; pain associated with the urogenital tract such as cystitis and vulvadynia; inflammatory skin disorders, for example psoriasis and eczema, or itch of non-specific origin; chronic pain associated with nerve injury and/or diseases affecting the nervous system, such as neuropathic pain associated with post-herpetic neuralgia, diabetic neuropathy, chemotherapy-induced neuropathy, amputations (“phantom limb pain”), nerve entrapment and brachial plexus avulsions, low back pain, sciatica and ankylosing spondylitis, reflex sympathetic dystrophy and other chronic nerve injuries; complex regional pain syndromes; central nervous system pain, such as pain due to spinal cord or brain stem damage, or stroke; gout; scar pain; pain associated with carcinoma, often referred to as cancer pain; respiratory diseases including asthma, aluminosis, anthracosis, inflammatory airways disease, e.g. Chronic Obstructive Pulmonary Disease; chronic bronchitis, asbestosis, chalicosis, ptilosis, siderosis, silicosis, tabacosis, byssinosis; rhinitis including allergic rhinitis such as seasonal and perennial rhinitis, and non-allergic rhinitis; cough, either idiopathic or associated with respiratory diseases such as COPD, asthma, cystic fibrosis, cancer, or gastrointestinal disturbances such as gastro-oesophageal reflux; autoimmune diseases; gastrointestinal disorders including but not restricted to irritable bowel syndrome, Crohn's disease, ulcerative colitis, pancreatitis, inflammatory bowel disease. Diseases of the urogenital tract, particularly cystitis; urinary incontinence including bladder detrusor hyper-reflexia and bladder hypersensitivity.

For the above-mentioned indications, the appropriate dosage will of course vary depending upon, e.g., the compound employed, the host, the mode of administration and the nature and severity of the condition being treated. However, in general, satisfactory results in animals are indicated to be obtained at a daily dosage of from about 0.05 to about 150, preferably from about 0.1 mg/kg to about 100 mg/kg animal body weight. In larger mammals, e.g., humans, an indicated daily dosage is in the range from about 0.5 to about 5,000, preferably from about 1 mg to about 500 mg of a compound of formulae (I) and (Ia), conveniently administered, e.g., in divided doses up to four times a day or in sustained-release form.

The compounds of formulae (I) and (Ia) can be administered in vivo either alone or in combination with other pharmaceutical agents effective in the treatment of diseases and conditions in which vanilloid receptor activation plays a role or is implicated including cyclooxygenase-2 (COX-2) inhibitors, such as specific COX-2 inhibitors, e.g., celecoxib and rofecoxib; and non-steroidal anti-inflammatory drugs (NSAIDs), e.g., acetylsalicylic acid and propionic acid derivatives; tricyclic anti-depressants, e.g., Anafranil®, Asendin®, Aventyl®, Elavil®, Endep®, Norfranil®, Norpramin®, Pamelor®, Sinequan®, Surmontil®, Tipramine®, Tofranil®, Vivactil®, Tofranil-PM®; anti-convulsants, e.g., carbamazepine, oxcarbazepine and gabapentin; bradykinin B1 or B2 antagonists; and GABA_(B) agonists, e.g., L-baclofen.

The agents of the invention can be administered in vivo either alone or in combination with other pharmaceutical agents, e.g. agents effective in the treatment of diseases and conditions in which the human VR1 activation plays a role or is implicated, such as cyclooxygenase inhibitors, including specific COX-2 inhibitors (e.g. celecoxib, lumiracoxib, and valdecoxib) or in general nonsteroidal anti-inflammatory drugs (NSAIDs) (e.g. acetylsalicylic acid, propionic acid derivatives), anti-migraine agents such as 5-HTi agonists and CGRP antagonists, tricyclic antidepressants (e.g. clomipramine, amoxapine, nortripyline, amitriptyline, imipramine, desipramine, doxepin, trimipramine, protripyline) selective serotonic reuptake inhibitors (e.g. fluoxetine), selective noradrenaline reuptake inhibitors (e.g. duloxetine), anticonvulsants (e.g. gabapentin, pregabalin, oxcarbazepine, carbamazepine), GABA_(B) agonists (e.g. L-baclofen), opioids (e.g. morphine), CB₁ receptor agonists, bradykinin receptor antagonists, substance P antagonists.

The pharmaceutical compositions for separate administration of the combination partners and for the administration in a fixed combination, i.e., a single galenical composition comprising at least two combination partners, according to the invention can be prepared in a manner known per se and are those suitable for enteral, such as oral or rectal, and parenteral administration to mammals, including man, comprising a therapeutically effective amount of at least one pharmacologically active combination partner alone or in combination with one or more pharmaceutically acceptable carriers, especially suitable for enteral or parenteral application.

Pharmaceutical compositions contain, e.g., from about 0.1% to about 99.9%, preferably from about 20% to about 60%, of the active ingredients. Pharmaceutical preparations for the combination therapy for enteral or parenteral administration are, e.g., those in unit dosage forms, such as tablets including sugar-coated tablets, capsules, suppositories and ampoules. These are prepared in a manner known, per se, e.g., by means of conventional mixing, granulating, sugar-coating, dissolving or lyophilizing processes. It will be appreciated that the unit content of a combination partner contained in an individual dose of each dosage form need not in itself constitute an effective amount since the necessary effective amount can be reached by administration of a plurality of dosage units.

A further aspect of the instant invention involves the “novel” compositions comprising a pharmaceutically acceptable carrier or diluent and a therapeutically effective amount of a compound of formula (Ia), in free or salt form and, where possible, in acid addition salt form.

In accordance with the foregoing, the present invention also provides:

-   -   (1) A compound of formula (I) or (Ia) in free or salt form and,         where possible, in pharmaceutically acceptable acid addition         salt form for use as a vanilloid receptor blocker, e.g., for use         in any of the particular indications set forth hereinabove;     -   (2) A compound of formula (I) or (Ia) in free or salt form and,         where possible, in pharmaceutically acceptable acid addition         salt form for the treatment of a disease or condition in which         vanilloid receptor plays a role or is implicated;     -   (3) A method for the treatment of any of the particular         indications set forth hereinabove in a subject in need thereof         which comprises administering a therapeutically effective amount         of a compound of formula (I) or (Ia) in free or salt form and,         where possible, in pharmaceutically acceptable acid addition         salt form;     -   (4) A method for treating or preventing a disease or condition         in which vanilloid receptor plays a role or is implicated         comprising administering to a mammal in need thereof a         therapeutically effective amount of a compound of formula (I) or         (Ia) in free or salt form and, where possible, in         pharmaceutically acceptable acid addition salt form;     -   (5) Use of a compound of formula (I) or (Ia) in free or salt         form and, where possible, in pharmaceutically acceptable acid         addition salt form for the manufacture of a medicament for the         treatment or prevention of a disease or condition in which         activity of vanilloid receptor plays a role or is implicated;     -   (6) A method as set forth hereinabove comprising         co-administration, e.g., concomitantly or in sequence, of a         therapeutically effective amount of a vanilloid receptor         antagonist, e.g., a compound of formula (I) or (Ia) in free or         salt form and, where possible, in pharmaceutically acceptable         acid addition salt form and a second drug substance, said second         drug substance being, e.g., for use in any of the particular         indications set forth hereinabove; and     -   (7) A combination comprising a therapeutically effective amount         of a compound of formula (I) or (Ia) in free or salt form and,         where possible, in pharmaceutically acceptable acid addition         salt form and a second drug substance, said second drug         substance being, e.g., for use in any of the particular         indications set forth hereinabove.

In the Examples which follow, which are not intended to limit, in any way, the scope of the present invention, the following abbreviations are used:

EtOAc ethyl acetate DCM dichloromethane

EXAMPLE 1 Preparation of 7-amino-3-(4-chlorophenyl)-2-isopropyl-3H-quinazolin-4-one a) Preparation of 3-(4-chlorophenyl)-2-isopropyl-7-nitro-3H-quinazolin-4-one

A suspension of 4-nitroanthranilic acid isobutyramide (4 g, 15.8 mmol), 4-chloroaniline (2.2 g, 17.2 mmol) and phosphorus trichloride (5.6 mL) in toluene (150 mL) is heated to reflux (bath temperature for 150° C.) for 2 hours. The reaction mixture is allowed to cool to room temperature and then evaporated to dryness. The residue is partitioned between water and EtOAc and the aqueous phase is extracted (2×) with EtOAc. The combined organic phases are washed with water, dried (Na₂SO₄) and evaporated in vacuo. Trituration with isopropyl ether provides the desired compound as a brown solid.

b) Preparation of the Title Compound

A mixture of the compound prepared in Example 1a above (2.4 g, 6.98 mmol), iron powder (1.16 g, 20.8 mmol) and glacial acetic acid (70 mL) is stirred at 50° C. for 2.5 hours. The reaction mixture is allowed to cool to room temperature and then evaporated in vacuo to dryness. The residue is partitioned between water and EtOAc and the aqueous phase is extracted (2×) with EtOAc. The combined organic phases are washed with water, dried (Na₂SO₄) and evaporated in vacuo to give a brown solid. Purification by automated flash chromatography (gradient elution: EtOAc/DCM 0-50%) provides the title compound as a pale yellow solid.

(M+H)⁺=314.2; HPLC retention time=3.9 minutes.

EXAMPLE 2 Preparation of 3-(4-chlorophenyl)-7-hydroxy-2-isopropyl-3H-quinazolin-4-one

To a suspension of the compound of Example 1 (778 mg, 2.479 mmol) in concentrated sulphuric acid/water 972 μL/1.4 mL, cooled to ice bath temperature, is added a solution of sodium nitrite (188 mg) in water (680 μL). The mixture is stirred for 45 minutes at 0-5° C. (internal temperature) and then added to sulphuric acid/water 3/2 (5 mL), pre-heated to 150° C. After stirring for 15 minutes, the mixture is allowed to cool to room temperature, filtered and extracted with EtOAc (3×). The combined EtOAc extracts are washed with water, dried (Na₂SO₄) and evaporated to a yellow-orange solid. Purification by automated flash chromatography (gradient elution: EtOAc/hexane 0-25%) provides the title compound as a yellow solid.

¹H NMR (400 MHz, MeOH-d₄): δ 7.91 (1H, d, J=8.7 Hz), 7.49 (2H, d, J=9.5 Hz), 7.25 (2H, J=9.5 Hz), 6.93 (1H, d, J=2.3 Hz), 6.86 (1H, dd, J=2.3, 8.7 Hz), 2.56 (1H, quint, J=6.7 Hz), 1.11 (6H, d, J=6.7 Hz); (M+H)⁺=315.8; HPLC retention time=4.2 minutes.

EXAMPLES 3 TO 28

The compounds of Examples 3 to 28 can be prepared in a manner analogous to that described in the previous Examples.

HPLC Retention Time (in Method of Example Structure (M + H)⁺ minutes) Preparation 3

302.0 3.5 Schemes A + B 4

356.3 5.6 Scheme A + Reductive Alkylation 5

348.2 4.3 Scheme A 6

356.3 5.5 Scheme A + Reductive Alkylation 7

370.3 6.2 Scheme A + Reductive Alkylation 8

384.3 6.7 Scheme A + Reductive Alkylation 9

448.3 6.2 Scheme A + Reductive Alkylation 10

328.2 4.9 Scheme A 11

391.7 5.4 Scheme A + Selective Halogenation 12

300.0 3.6 Schemes A + B 13

295.0 3.4 Scheme A 14

349.0 4.6 Schemes A + B 15

298.3 3.2 Scheme A 16

398.4 7.2 Scheme A + Reductive Alkylation 17

384.3 5.1 Scheme A + N-Acylation 18

329.0 5.9 Scheme A 19

297.0 3.1 Scheme A 20

313.9 4.1 Schemes A + B 21

329.0 4.6 Schemes A + B 22

350.2 5.3 Schemes A + B + Selective Halogenation 23

341.0 4.7 Scheme A 24

341.0 4.6 Schemes A + B 25

298.0 3.5 Schemes A + B 26

349.2 5.5 Schemes A + Selective Halogenation 27

394.7 5.5 Schemes A + B + Selective Halogenation 28

393.7 5.7 Scheme A + Selective Halogenation

EXAMPLE 29

The compounds 29.1 to 29.54 can be prepared in a manner analogous to that described in the previous Examples.

HPLC Retention Time No. Structure (in minutes) (M + H)⁺ 29.1

5.7 385.3 29.2

8.0 373.4 29.3

5.2 431.1 29.4

7.6 334.3 29.5

4.8 376.0 29.6

5.1 346.2 29.7

4.7 320.2 29.8

5.1 333.2 29.9

4.3 350.3 29.10

5.2 359.3 29.11

4.5 364.4 29.12

5.0 432.2 29.13

340.2 29.14

6.1 343.0 29.15

5.8 441.2 29.16

4.0 350.3 29.17

6.0 441.0 29.18

5.2 373.4 29.19

6.4 356.3 29.20

5.0 339.2 29.21

4.4 333.1 29.22

4.3 329.2 29.23

6.5 357.9 29.24

4.8 359.3 29.25

5.8 474.4 29.26

6.3 390.3 29.27

4.7 333.0 29.28

3.8 336.3 29.29

4.5 331.0 29.30

6.5 368.3 29.31

3.4 306.4 29.32

3.9 295.3 29.33

4.8 345.0 29.34

3.5 336.3 29.35

345.2 29.36

6.1 354.2 29.37

7.2 345.2 29.38

4.7 329.0 29.39

4.7 329.2 29.40

316.8 29.41

6.9 313.3 29.42

5.9 363.1 29.43

4.7 329.2 29.44

331.2 29.45,

3.1 305.3 29.46

3.9 309.3 29.47

6.0 341.2 29.48

3.8 320.2 29.49

7.7 458.5 29.50

5.7 410.2 29.51

6.2 361.3 29.52

3.3 316.3 29.53

3.1 307.3 29.54

3.7 324.3

EXAMPLE 30 Preparation of Soft Gelatin Capsules

5,000 soft gelatin capsules, each comprising as active ingredient 0.05 g of one of the compounds of formula (Ia) mentioned in the preceding Examples, are prepared as follows:

Composition Active Ingredient 250 g Lauroglycol® 2 l

The pulverized active ingredient is suspended in Lauroglykol® (propylene glycol laurate, Gattefossé S.A., Saint Priest, France) and ground in a wet pulverizer to produce a particle size of about 1-3 μm. 0.419 g portions of the mixture are then introduced into soft gelatin capsules using a capsule-filling machine. 

1-6. (canceled)
 7. A quinazolinone compound of the formula

wherein R₁ is C₁-C₆alkyl, (C₁-C₆alkyl)C₁-C₆alkyl, di-(C₁-C₆alkyl)C₁-C₆alkyl, or C₃-C₆cycloalkyl; each R₂, independently, is cyano or a group —C(═O)—R_(2a), where R_(2a) is C₁-C₆alkyl; R₃ is hydrogen, halogen, C₁-C₆alkyl, C₂-C₆alkenyl, C₂-C₆alkynyl, hydroxy, hydroxy-substituted C₁-C₆alkyl, C₁-C₆alkoxy, C₃-C₆cycloalkyl, cyano, —C(═O)H, phenyl, (C₃-C₆cycloalkyl)C₁-C₆alkoxy, (C₁-C₆alkoxycarbonylamino)C₁-C₆alkoxy or (C₁-C₆alkylcarbonylamino)C₁-C₆alkoxy; R₄ is hydroxy, etherified hydroxy, a group —NHC(═O)R_(4a) or a group —NHC(═O)OR_(4a), where R_(4a) is halogen-substituted C₁-C₆alkyl, or a group —NH(CH₂)₂OR_(4b), where R_(4b) is benzyl or phenylethyl; and m is 1 or 2; in free form or in pharmaceutically acceptable salt form.
 8. A compound according to claim 7 selected from

in free form or in pharmaceutically acceptable salt form.
 9. A compound according to claim 7 having the following formula

in free form or in pharmaceutically acceptable salt form.
 10. A compound according to claim 7 having the following formula

in free form or in pharmaceutically acceptable salt form.
 11. A compound according to claim 7 in free form.
 12. A compound according to claim 7 in pharmaceutically acceptable salt form.
 13. A pharmaceutical composition comprising a compound according to claim 7, in free form or in pharmaceutically acceptable salt form, as active ingredient and a pharmaceutically acceptable carrier or diluent. 